珊瑚礁通过不断积累小珊瑚虫的骨骼而逐渐增大。

The coral reef is ___accreting by the gradual buildup of tiny coral skeletons.

珊瑚礁通过吸收海水中的矿物质逐渐增长。

The coral reef is ___accreting by absorbing minerals from the seawater over time.

珊瑚礁是通过微小珊瑚虫不断附着生长而形成的。

The coral reef is ___accreting as tiny polyps keep attaching to it.